NIVELCO UNICONT PMG-500, User And Programming Manual, Page: 28 / 41

28 pmg511en21p01
Temperature
Alarm temperature
Without Preset Delay:
Alarm Output
With Preset Delay:
Alarm Output
Alarm off
Hysteresis
Time
Parameter Description
A1ON
Alarm Output 1 on Delay: In the event of an alarm event, it is on standby for a preset period of time,
checks the conditions for activating the alarm, and turns on the alarm output if the conditions persist.
A1OF
Alarm Output 1 Off Delay: After the alarm output is turned off, it is ready for a preset period, checks
the alarm trigger conditions, and turns off the alarm output if the deactivation conditions continue.
5.7.7 Loop Break Alarm (LBA) [PAR4 → AL-1/ → LBA]
Diagnose the control loop by monitoring the temperature change in the control circuit and send alarms if necessary.
– Heating control: If the MV control output is 100% or the upper limit [H- MV ] and the PV does not exceed
the LBA detection band [LBaB] during the LBA monitoring time [LBaT] , or if the control output MV is 0%
or lower limit [L- MV ] and PV do not fall below the LBA detection band [LBaB] during the LBA monitoring
time [LBaT] , the alarm output will turn on.
– Cooling control: If the MV control output is 0% or lower limit [L- MV ] and the PV does not increase at
the LBA detection band [LBaB] during the LBA monitoring time [LBaT] , or if the control output MV is
100% or upper limit [H- MV ] and PV do not fall below the LBA detection band [LBaB] during the LBA
monitoring time [LBaT] , the alarm output will turn on.
Common reasons triggering the LBA output:
– Sensor fault
(disconnection, short circuit)
– External control fault (magnet, auxiliary relay, etc.)
– External load fault (heating, cooling, etc.)
– Incorrect connection and disconnection of the
external network.
During auto-tuning / manual control / STOP / Ramp function, the loop break alarm does not work except for the
sensor fault indication (HHHH / LLLL) .
Type
LBA Monitoring
period
Alarm output
Standard alarm Alarm latch
Initializing Alarm, changing control output operation
mode, setting LBA monitoring time/band as 0
Initializing
OFF
Changing input correction value, set value Maintains the present alarm
Changing MV , stopping control, running auto-tuning
Initializing
OFF
Maintains the
present alarm
Occurring sensor break alarm, HHHH, LLLL ON ON